The importance of sensors that can read mechanical stimuli in biometric integrated electronic devices or flexible integrated electronic circuits that detect sophisticated bio-signals or detect minute stresses is increasing. However, recently developed flexible sensors are difficult to detect accurate signals due to their low sensitivity.
To solve this sensitivity problem, a crack sensor has been developed which simulates the crack structure of a spider's vibrating sensory organs. These crack sensors have sensitivity close to 2,000 in the 2% strain range. However, due to the structural effect of the crack, the stress accumulates, and the crack deepens, and, eventually, the sensitivity decreases. Particularly, after about 1,000 repeated tests, the cracks become deep or broken, resulting in a decrease in sensitivity and stability.